It has been known a method of magnetic treatment of crop seeds as one method for improvement including facilitating the growth of crops such as grain, vegetable, flower and the like, improving the crop thereof, and adapting them to their growing environment. For example, Japanese Patent Laid-open No. 51721/1981 discloses a method of magnetic treatment comprising exposing seed in dry state to a single-pole magnetic field of 600 to 3500 Gauss and rotating or shaking the seed for a period of 5 seconds to 14 hours. The Japanese Patent Laid-open describes in detail the results of growing seeds of corn, Japanese radish and the like through magnetic treatment under variable conditions concerning the intensity of a magnetic flux density, the type of single magnetic field, i.e., N pole and S pole, the exposing time, as well as the change in the plant properties. However, as the apparatus for magnetic treatment, apparatuses utilizing permanent magnet and electromagnet are employed in the method, and it has been hard in the steps of germination and seedling growing to apply efficient magnetic treatment in consistent manner for a certain period of time.
Furthermore, the effect of magnetic treatment of facilitating growth of seeds of barley and wheat is reported by U. J. Pittmam, in Can. J. Plant Sci. 57 pp 37-45 (1976).
On the other hand, the seeding work of grain, vegetable, flower and the like has conventionally been carrid out manually, but the recent decrease in the number of farmers as well as the progress of their aging involves the enhanced importance of improving the seeding method. Furthermore, as seeds have not had uniform quality ordinarily, there has been taken a working procedure such that once seeds of the excessive number than necessary are planted, the germinating plants are thinned out. However, the recent remarkable improvement in the quality of seeds and their germinating ratio caused by the progress in F.sub.1 seed hybridization needs the dramatic decrease in seeding amount.
Additionally, in the hydroponic culture of which application field has recently been enlarged rapidly, there has been employed a procedure comprising placing a predetermined number of seeds on a small area seedling-growing mat including one made of urethane form, at predetermined interval, and permanently planting the seedlings after germinating the seeds and growing the seedlings, wherein seeding is generally done manually since seeds are in a wide variety of size and shape.
Because the conventional techniques have some problems insofar mentioned, the expectation toward their improvement has been intense. The objective of the present invention is to solve the problems involved in the conventional techniques and to provide a seeding and seedling-growing sheet and a seeding and seedling-growing method, capable of efficiently and continuously promoting growth of germinating seeds and seedlings and efficiently placing seeds at a desirable position of a seedling-growing mat or a seedling-growing bed, at a desirable density with a higher positional precision.